News Release

Time：2016-09-29Browse Number：484Source：Michael Irving, newatlas.com

(September 5) Alongside
green energy production, capturing carbon emissions at the source is another
avenue in the fight against climate change. New materials and treatments are
regularly improving carbon capture efficiency, and now scientists have
developed an efficient low-cost technique that makes use of an ultra-thin
membrane, like a bubble, to filter CO2 out of flue gas.

The
researchers, from Sandia National Laboratories and the University of New
Mexico, call their creation a CO2 Memzyme – a membrane full of enzymes. With a
liquid layer 10 times thinner than a soap bubble, CO2 diffuses through this
membrane and is captured and dissolved, while allowing nitrogen and oxygen to
pass through. Bubbles are notoriously fragile, though, so to prevent breaks or
leakage, the team bolstered theirs with a silica-based support of nanopores,
made up of a relatively thick layer that repels water, and a thin layer that
attracts it.

Scientists have developed a thin, bubble-like membrane which could help filter CO2 out of flue gas.

Enzymes
were added to the liquid layer to help speed up the C02 dissolution process.
The team used carbonic anhydrase, an enzyme found in human muscles, blood and
lungs that helps the body process and remove carbon dioxide, and found that it
increased the rate that the CO2 dissolved by a factor of 10 million. With the
nanopores forming an unusual environment for the enzymes, the researchers ran
molecular simulations to figure out how the carbonic anhydrase was behaving in
the cramped conditions and see how they might improve its performance.

The
simulations showed that although the nanopores aren't much bigger than the
enzymes themselves, several of them could cram into the space and work together
to help process the CO2. The nanopore structure helped protect the enzymes as
well, meaning they could stay dissolved and active in much higher
concentrations than usual, and do so for months on end, at temperatures as high
as 140° F (60° C).

Altogether,
the team claims their design is 10 to 100 times more selective for CO2 over
nitrogen in passing flue gas than existing carbon capture membranes, and it
performs 100 times faster. At the other end, the CO2 that's produced is 99
percent pure, which can be used in a variety of ways, like manufacturing
concrete or producing biofuel from bacteria and algae.

While
the team is currently seeking out partners to help scale the technology up for
use in power plants, lab tests have shown promise.

"If
we applied it to a single coal-fired power plant, then over one year we could
avoid CO2 emissions equivalent to planting 63 million trees and letting them
grow for 10 years," says Rempe.

The
team received a patent for the Memzyme technology earlier this year and,
although it's still early days, say it could be the first to meet the
Department of Energy's national clean energy goal of having technology that can
capture 90 percent of carbon emissions at a cost of US$40 per ton by 2025.